s3:smbd - support streams larger than 64 KiB

s3:smbd - support streams larger than 64 KiB

Add support for streams that are larger than 64 KiB in size. Upper
and lower bound are controlled by the parameters smbd max_xattr_size.
Testing against ReFS on Windows (where ADS size is limited in size
shows the server responding with STATUS_FILESYSTEM_LIMITATION.
Do the same in samba for this case.

Currently, large xattrs are supported in FreeBSD.

Signed-off-by: Andrew Walker <awalker@ixsystems.com>
Reviewed-by: Jeremy Allison <jra@samba.org>
Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Mon May 10 20:16:21 UTC 2021 on sn-devel-184